When starting internal combustion engines in cold weather it is desirable to let the engine idle for a period of time in order to bring the engine up to a satisfactory operating temperature before putting it to work. In very cold weather, and with larger diesel engines such as those used in locomotives it can take a considerable period of time to reach operating temperature. It is also often very difficult to start a cold engine in some conditions, and once started considerable wear takes place before the engine oil warms up enough to provide satisfactory lubrication. For these reasons locomotive engines are often not shut down at all but left idling continuously emitting exhaust into the environment. Fuel costs for an idling locomotive engine are significant, and since the engine is running, unnecessary wear is taking place on engine parts.
This problem has been addressed in U.S. Pat. No. 4,711,204 to Rusconi and U.S. Pat. No. 6,470,844 to Beiss by providing a second smaller internal combustion engine that will warm and circulate coolant and lubricating oil, maintain charge in batteries, and so forth when the locomotive engine is shut down. Exhaust gas and coolant from the smaller engine, and inefficient pump operation, provide heat that is transferred to the oil and coolant through heat exchangers.
U.S. Pat. No. 4,249,491 to Stein discloses a system for heating and circulating both the oil and coolant in a locomotive engine. Both oil and coolant are circulated through a two-compartment tank. The coolant passes through an inner compartment of the tank where it is heated by contact with an electric element or some like heat source, and the oil passes through an outer compartment where it picks up heat from the heated coolant, but is protected from direct contact with the element.
The above systems are directed to heating a single vehicle engine. Vehicle engines require a great deal of energy to heat. Locomotive engines can have cooling systems with 900 liter capacities, which require the heating system to warm 900 liters of coolant. Modern engines also commonly come with aluminum pistons which can draw large amounts of heat out of the engine block. Because of the large amounts of heat required to keep a vehicle engine at a sufficient temperature, electric heating elements are often not powerful enough to sustain the engine at a sufficient level without specialized power supplies that can supply very large amounts of electricity. Stein discloses the limitation of heating systems in relation to keeping a vehicle engine warm and deals with it by heating both the coolant and oil system with the same electrical element. The prior art mention above is primarily concerned with attempting to keep one vehicle engine at a sufficient temperature and the apparatuses and methods disclosed are insufficient to heat multiple engines using a single heat source.